JPH03136968A - Antiskid brake control system - Google Patents

Abstract

PURPOSE:To carry out the antiskid control in order to reduce the variation of G as small as possible by providing a feeder passage to detour a flow regulating valve, and a check valve arranged in the detouring feeder passage. CONSTITUTION:The first brake system A and the second brake system B are quite same. A check vale 22 to allow only the flow of the brake liquid from the output port 2a of a control valve 2 to a wheel cylinder 3 is provided in a feeder passage 16. The antiskid brake system is set to the control modes shown in the list, by the operation conditions of the first flow passage changeover valve 10 and the first flow regulation valve 13. In this case, when a sudden pressure reduction mode is transferred to a sudden pressure increase mode, a holding mode is being set, and thereby the brake fluid pressure is not varied so suddenly.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an anti-skid brake control system for a vehicle, and is a patented invention.During amplifier skid brake control, brake fluid pressure is controlled by switching between a slow-sudden pressure reduction mode and a slow-slow pressure increase mode. The present invention relates to an anti-skid brake control system that is provided with a flow path switching valve and a flow rate adjustment valve.

(Prior art) In general, anti-skid brake control, when it is detected that a wheel is in a skid state during braking, reduces the braking force on that wheel to eliminate the skid state of the wheel, and then increases the braking force again. This will stabilize the vehicle's handling.

Brake control is performed so that the braking distance is as short as possible.

(Problems to be Solved by the Invention) As an example of an anti-skid brake control system that performs such brake control, the one shown in FIG. 5 can be considered.

As shown in FIG. 5, in this anti-skid brake control system, hydraulic pressure from a hydraulic pressure source 1 consisting of a pump 1a and an accumulator 1b is applied to a wheel cylinder 3 for the front right wheel and a wheel cylinder 3 for the left rear wheel via a first control valve 2. The hydraulic pressure of the first brake system A and the hydraulic pressure source 1, which are supplied to the wheel cylinders 4 for wheels, respectively, is supplied to the wheel cylinder 6 for the left front wheel via the second control valve 5.
and a second brake system B which is supplied to the wheel cylinder 7 for the right rear wheel, respectively. Since the first and second brake systems A and B have the same configuration, the first brake system A will be described hereafter, and the description of the second brake system B will be omitted.

In the first brake system A, the first control valve 2 is composed of a three-bottom, three-position valve, and the output port 2a of the control pulp 2 and the wheel cylinder 3 for the right front wheel are connected via the first supply passage 8. and is in communication with the output port 2 of the first control valve 2.
a and the wheel cylinder 4 for the left rear wheel are connected to the second supply passage 9
communicated via.

The first and second supply passages 8.9 are provided with a first passage switching valve 10 and a second passage switching valve 11, respectively, which are electromagnetic valves. These first and second flow path switching valves 10.1
1 is adapted to selectively switch between communicating the wheel cylinders 3 and 4 with the output port 2a of the first control valve 2, or communicating the wheel cylinders 3 and 4 with the reservoir tank 12, respectively. There is. In the illustrated normal state, the first and second flow path switching valves 10
．． 11 is set to communicate the wheel cylinder 3.4 with the output port 2a and to isolate it from the reservoir tank 12.

In addition, the first and second supply passages 8 and 9 are located upstream of the first and second flow path switching valves 10.11 to selectively communicate the output port 2a and the wheel cylinder 3.4. Alternatively, first and second flow regulating valves 13 and 14 made of mechanical pulp to shut off are provided, respectively. These first and second flow rate regulating valves 13 and 14 open the first and second supply passages 8 and 9 in the illustrated normal state, and also ensure that the pressure on the output boat 2a side and the pressure in the wheel cylinders 3 and 4 are equal to each other. When a predetermined pressure difference is reached, the switch is switched to cut off the first and second supply passages 8 and 9.

Furthermore, the output port 2a includes a first orifice 15,
It communicates with the wheel cylinder 3 via a third supply passage 16 that bypasses the first flow rate adjustment valve 13 and the first flow path switching valve 10, and is equipped with a second orifice 17, bypassing the second flow rate adjustment valve 14. It communicates with the wheel cylinder 4 via a fourth supply passage 18 and a second passage switching valve 11.

Furthermore, the second supply passage 9 between the second passage switching valve 11 and the wheel cylinder 4 is provided with a provisioning valve PVI 9.

On the other hand, the reservoir tank 12 is connected to the suction side of the pump 1a, and the discharge side of the pump 1a is connected to the accumulator 1b and the input port 2 of the first control valve 2.
It communicates with b. Further, the first and second control valves 2.5 are connected to a brake pedal 21 via an equalizer 20. When the brake is not activated as shown in the figure, the first and second control valves 2.5 are set at the first position where the output port 2a and the discharge boat 2C communicate with each other, and when the brake pedal 21 is depressed, the three control valves 2.5 The second boat where boats 2a, 2b, 2c are isolated from each other
By further depressing the brake pedal 21, the output port 2a and the input port 2b are set to a third position where they communicate with each other.

By the way, the first flow path switching valve 10 and the first flow rate adjustment valve 13
Depending on each operating state, the anti-skid brake control system is set to a control mode as shown in Table 1. That is, Table 1 Control mode of anti-skift vehicle brake Next,
The operation of the anti-skid brake control system of this embodiment will be explained.

Normally, each valve 10, 11, 13.14 is in the state shown, and the output boat 2a and the wheel cylinder 3.4 are in communication. Therefore, when the brake pedal is depressed and the first control valve 2 is set to the third position during braking, the hydraulic pressure of the hydraulic pressure source 1 is transferred to the wheel cylinder 3 for the right front wheel via the first and second supply passages 8.9. The brakes of the front right wheel and the rear left wheel are respectively operated.

When it is detected that the front right wheel is likely to skid, the solenoid of the second flow rate adjustment valve 13 is energized by the detection signal, so the second flow rate adjustment valve 13 shuts off the first supply passage 8. . Therefore, brake fluid is supplied to the wheel cylinder 3 of the right front wheel only through the third supply passage 16 provided with the orifice 15. Therefore, the brake fluid pressure in the wheel cylinder 3 of the right front wheel gradually increases, and the mode becomes a slow pressure increase mode. Even in this gradual pressure increase mode, if the front right wheel is about to skid, the solenoid of the first flow path switching valve 10 is energized.
As the flow path switching valve 10 switches, the first flow rate regulating valve 1
3 switches to normal state. This allows output boat 2
A and the wheel cylinder 3 are cut off, and the flow path of the brake fluid is switched so that the wheel cylinder 3 is communicated with the reservoir tank 12, and the first supply passage 8 is communicated with the brake fluid. Therefore, the brake fluid in the wheel cylinder 3 rapidly flows out into the reservoir tank 12, so that the brake fluid pressure in the wheel cylinder 3 rapidly decreases and enters a rapid pressure reduction mode, and the braking force on the right front wheel is rapidly weakened. When the brake fluid pressure in the wheel cylinder 3 is reduced by a predetermined amount, the first flow regulating valve 13 is switched again to
Supply passage 8 is blocked. Therefore, the brake fluid in the wheel cylinder 3 gradually flows out into the reservoir tank 12, so that the brake fluid pressure in the wheel cylinder 3 gradually decreases to a slow pressure reduction mode, and the braking force on the right front wheel is gradually weakened.

When the skid condition of the right front wheel is resolved, both valves 10.1
When both solenoids No. 3 are turned off and the output boat 2a and the wheel cylinder 3 are communicated with each other, the brake fluid flow path is switched so that the wheel cylinder 3 and the reservoir tank 12 are disconnected, and the first supply path 8 is switched off. communicate. As a result, the brake fluid pressure in the wheel cylinder 3 rapidly increases to enter the rapid pressure mode, and the braking force on the right front wheel is rapidly increased.

In this way, the brake fluid pressure II is controlled so that the distance of movement per brake force is as short as possible to eliminate skids. The control characteristics in this case are as shown in FIG.

Anti-skid control is performed in the same way as described above even when other wheels are in a skid state.

However, with such an anti-skinned brake control system, it is controlled in the four modes shown in Table 1 above, so there is no direct transition from pressure increase mode to pressure decrease mode or from pressure decrease mode to direct pressure increase mode. That's how it is. For this reason.

When changing to another mode, not only will fluctuations in E and G (acceleration/deceleration) become large, but also brake fluid pressure fluctuations will increase, resulting in a large kickback to the brake pedal, which will affect ride comfort and driving feeling. The problem is that it gets worse.

Furthermore, in order to minimize brake fluid pressure fluctuations, the operation of the flow path switching valve 10 and the flow rate adjustment valve 13 must be finely controlled, which increases the number of times these valves are operated. Therefore, the flow path switching valve and the flow rate regulating valve must be made with excellent durability, which increases the cost.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an anti-skid brake control system that can perform anti-skid control so as to minimize fluctuations in G. .

Another object of the present invention is to provide an anti-skid brake control system that can reduce the number of times the flow path switching valve and flow rate regulating valve are operated, thereby allowing these valves to be formed at low cost. It is.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a supply passage that communicates between a brake fluid pressure generating means and a wheel cylinder that generates a brake force for a wheel, and a supply passage provided in the supply passage. is,
a flow path switching valve that operates when a skid state of the wheel is detected during braking and releases brake fluid supplied to the wheel cylinder to a reservoir tank; and the supply between the flow path switching valve and the wheel cylinder. A flow rate adjustment valve provided in the passage that shuts off the supply passage only in a predetermined control mode in anti-skid brake control and opens the supply passage at other times, and an orifice provided in parallel with the flow rate adjustment valve. The present invention is characterized in that it includes a supply passage that bypasses the flow rate adjustment valve, and a check valve disposed in the supply passage that bypasses the flow rate adjustment valve.

(Operation) In the anti-skid brake control system according to the present invention having such a configuration, the check valve is disposed in series with the orifice in the supply passage that bypasses the flow rate regulating valve. Therefore, either the slow pressure reduction mode or the slow pressure increase mode of the brake fluid pressure during anti-skid brake control is set to the brake fluid pressure maintenance mode.

By setting this holding mode when transitioning from sudden pressure reduction mode to sudden pressure reduction mode or from sudden pressure reduction mode to sudden pressure reduction mode, it becomes possible to suppress sudden fluctuations in brake fluid pressure. .

By arranging the check valve so as to allow only the flow of brake fluid toward the wheel cylinder, a slow pressure increase mode, a sudden pressure decrease mode, and a holding mode can be set. Moreover, by arranging the check valve so as to only allow the flow of brake fluid in a direction away from the wheel cylinder, a gradual pressure reduction mode, a rapid pressure reduction mode, and a holding mode can be set.

(Example) Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a system circuit diagram similar to FIG. 5, schematically showing an embodiment of the anti-skid brake control system according to the present invention. Note that the same components as those in the anti-skid brake control system described above are given the same reference numerals, and their explanations will be omitted. Furthermore, as described above, the first brake system A and the second brake system B are completely the same, so only the first brake system A will be explained and the second brake system B will be omitted.

As shown in FIG. 1, in this embodiment, a check valve 22 is provided in the third supply passage 16 to allow only the flow of brake fluid from the upstream side to the downstream side, that is, from the output boat 2a to the wheel cylinder 3. There is. This check valve 22 may be provided either upstream or downstream of the orifice 15.

In the anti-skid brake control system of this embodiment, control modes as shown in Table 2 are set depending on the operating states of the first flow path switching valve 10 and the first flow rate regulating valve 13.

That is, Table 2 Control motes of anti-skiff rake.

Therefore, in this embodiment, among the control modes in the anti-skid brake control system as shown in FIG. 5, the holding mode is set instead of the slow pressure reduction mode.

The operation of this embodiment is the same as the anti-skid brake control system described above, except that the slow pressure reduction mode becomes the holding mode, so a description thereof will be omitted. As shown in FIG. 2, the control characteristics of this embodiment are such that the holding mode is set when transitioning from the rapid pressure reduction mode to the rapid pressure increase mode, so the brake fluid pressure does not fluctuate so rapidly.

FIG. 3 is a system circuit diagram similar to FIG. 5 schematically showing another embodiment of the anti-skid brake control system according to the present invention. Note that the same components as those in the anti-skid brake control system described above are given the same reference numerals, and their explanations will be omitted. Furthermore, as described above, the first brake system A and the second brake system B are completely the same, so only the first brake system A will be explained and the second brake system B will be omitted.

As shown in FIG. 3, in this embodiment, a check valve 23 is installed in the third supply passage 16 to allow only the flow of brake fluid from the downstream side to the upstream side, that is, from the wheel cylinder 3 to the output boat 2a. ing. This check valve 2
3 may be provided either upstream or downstream of the orifice 15.

Depending on the operating states of the first flow path switching valve 10 and the first flow rate regulating valve 13, the anti-skid brake control system of this embodiment has control modes as shown in Table 3.

That is, Table 3 Anti-skift brake control modes Therefore, in this embodiment, the holding mode is set in place of the slow pressure increase mode among the control modes in the anti-skid brake control system as shown in FIG. 5 described above. .

The operation of this embodiment is the same as that of the anti-skid brake control system described above except that @pressure increase mode becomes holding mode, so a description thereof will be omitted. The control characteristics of this embodiment are as shown in FIG. 4. Since the holding mode is set when transitioning from the rapid pressure increase mode to the rapid pressure reduction mode, the brake fluid pressure does not fluctuate so rapidly.

In this way, in any of the above-mentioned embodiments, the brake fluid pressure holding mode is set when transitioning from sudden pressure reduction to sudden pressure reduction or from sudden pressure reduction to sudden pressure reduction. Since there are no large fluctuations, there is no large fluctuation in G, and there is no large kickback to the brake pedal. Therefore, even during anti-skid brake control, a comfortable ride and a good driving feeling can be obtained.

Note that the present invention is not limited to the above-described embodiments, and various design changes are possible.

For example, in any of the embodiments described above, the holding mode is set only once, but the gradual and rapid pressure reduction mode, the slow and rapid pressure increase mode, and the holding mode can be combined as appropriate. By doing so, even more appropriate anti-skid control can be performed.

Furthermore, in the above embodiment, the check valves 22 and 23 are provided only in the front wheel brake system, but these check valves may be provided in the rear wheel brake system or in both the front and rear brake systems. You can also do it.

In the above-described embodiment, the brake piping is arranged in a diagonal system, but the present invention can also be applied to other piping systems. Further, the present invention can be applied to other channel systems other than the four-channel system in which the front and rear wheels are independent as in the above embodiment, such as a three-channel system in which the left and right front wheels and rear wheels are independent.

Further, in the embodiments described above, the present invention is applied to two systems of brake circuits, but it goes without saying that it can also be applied to one system of brake circuits.

(Effects of the Invention) As is clear from the above explanation, in the anti-skid brake control system according to the present invention, the holding mode is set when transitioning from the sudden pressure reduction mode to the rapid pressure reduction mode or from the sudden pressure reduction mode to the sudden pressure reduction mode. This makes it possible to keep brake fluid pressure fluctuations relatively low. Therefore, G does not vary greatly, and the ride quality during anti-skid brake control becomes comfortable.

Moreover, since brake fluid pressure fluctuations can be kept relatively low, kickback to the brake pedal is also suppressed, resulting in a good driving feeling.

In addition, by keeping brake fluid pressure fluctuations low,
Since the flow rate switching valve and the flow rate regulating valve do not need to be highly durable, these valves can be formed at low cost.

[Brief explanation of the drawing]

Fig. 1 is a control circuit diagram schematically showing an embodiment of the anti-skid brake control system according to the present invention, Fig. 2 shows the control characteristics of this embodiment, and Fig. 3 is the anti-skid brake control system according to the present invention. 4 is a diagram showing control characteristics in this embodiment; FIG. 5 is a control circuit diagram schematically showing an anti-skid brake control system considered as an example; FIG. 6 is a control characteristic diagram of this control circuit. 1...Fluid pressure source (brake fluid pressure generation means), 2.5...
・Control valve (brake fluid pressure generation means), 3.
...Wheel cylinder of the right front wheel, 4...Wheel cylinder of the left rear wheel, 6...Wheel cylinder of the left front wheel, 7...Wheel cylinder of the right rear wheel, 8...First supply passage, 9 ...Second supply passage, 10...First flow path switching valve, 11...Second flow path switching valve, 12...Reservoir tank 13...First flow rate adjustment valve, 14...
Second flow rate regulating valve, 15...First orifice, 16...
・Third supply passage (detour supply passage), 17...Second orifice, 18...Fourth supply passage, 21...Brake pedal, 22.23...Check valve

Claims (3)

[Claims] (1) A supply passage communicating between a brake fluid pressure generating means and a wheel cylinder that generates braking force for the wheels, and a supply passage provided in this supply passage, which is activated when a skid state of the wheel is detected during braking to cause the wheel to brake. A flow path switching valve that releases brake fluid supplied to the cylinder to a reservoir tank;
A flow rate adjustment device that is provided in the supply passage between the flow path switching valve and the wheel cylinder, and that shuts off the supply passage only in a predetermined control mode in anti-skid brake control, and opens the supply passage at other times. It has a valve, an orifice provided in parallel with the flow rate adjustment valve, a detour supply passage that bypasses the flow rate adjustment valve, and a check valve disposed in the detour supply passage. Anti-skid brake control system. (2) The anti-skid control brake system according to claim 1, wherein the check valve is arranged so as to allow only the flow of brake fluid toward the wheel cylinder. (3) The anti-skid control brake system according to claim 1, wherein the check valve is arranged so as to only allow the flow of brake fluid in a direction away from the wheel cylinder.